Brachial Plexus , Supraclavicular Exposure

Abstract

The supraclavicular brachial plexus includes the roots and the trunks. The brachial plexus is usually formed by the ventral rami of the spinal nerves from C5 to T1. Contribution is very common from C4 (prefixed) and uncommon from T2 (postfixed). It forms between the scalenus anterior and scalenus medius muscles and lies in the posterior triangle of the neck (bound by the sternocleidomastoid [SCM], the trapezius, and the clavicle). C5 and C6 join to make the upper trunk, C7 continues as the middle trunk, and C8 and T1 join to make the lower trunk. The suprascapular nerve (C5, C6) is the largest branch at the root/trunk level. It arises from the cranial aspect of the upper trunk, close to the divisions. The dorsal scapular nerve (to rhomboids and levator scapulae) comes off the C5 ventral ramus; the long thoracic nerve (to serratus anterior) comes off the C5, C6, and occasionally C7 ventral rami and usually runs through the scalenus medius muscle. The nerve to subclavius (C5, C6) comes off the upper trunk.